The invention concerns the realization of a container for lead-acid storage batteries acid storage batteries, particularly suited for static industrial lead.
It is known to the experts in this field that during operation of a battery the poles of lead-acid storage batteries are subject to lengthening, especially the positive pole. This characteristic is particularly relevant for industrial lead-acid storage batteries where the elements may become longer than 650 mm. In the lead-acid storage batteries of the known type the lengthening of the poles is accommodated either by connecting the lid to the container by means of a high yield point adhesive agent, or by using lids with a properly shaped surface, or lids on which the pole seats are shaped in such a manner as to make them elastic and yielding.
The known lead-acid storage batteries realized according to such characteristics have some inconveniences, i.e. the possibility for the lid or the container to become damaged during the disassembly phase when the lid is glued to the container itself, or a high manufacturing cost of molds in case the lead-acid storage batteries are realized with leads having their external surfaces or the poles seats showing such special configurations as to make them elastic and yielding.
It is also known to the experts in this field that the lead-acid storage batteries are made of plastic material, for example polypropylene, and are realized using the injection molding technique. The thickness of the container walls varies from a minimum of 2 mm to a maximum of 4 mm, where the thickness depends on the container dimensions and is considered to be optimal in order to provide a satisfactory resistance to mechanical stress on of the container itself.
One of the disadvantages of such containers is the high production costs which are due both to the high cost of the molds and to the considerable quantity of raw material necessary to produce each container.